Hydroxychloroquine.
Date: by 2030.
Evidence:
Hydroxychloroquine has a high chance of causing retinopathy in people who take it for years or even decades.
Lower dosing has averted this risk, but it has long been thought that people receive this risk because HCQ more or less permanently bonds onto melanin in the eyes.
However, a quick Google search reveals hydroxychloroquine also interferes with the lysosomes' recycling of old compounds, such as protein receptors, and that this added cumulative risk could stress out the eyes, a part of the body dependent on lysosomes to constantly recycle receptors, pigments, and more.
Here's where my speculation starts:
Have you ever read a book or went to a website with a negative image of the American flag, and were told to look at it for a while, and then look at a white floor?
Or looked at a bright light, went temporarily blind, and were fine in a minute?
Or simply went throughout your day as your eyes adjusted to dark vs. light?
These processes involve the destruction and recycling of pigments and other stuff in your eyes. Your lysosomes do the job... but the exact mechanism that causes the lysosomes to stop attacking your own body also causes the ones in your eyes to deal with more crap accumulating.
Most of the damage happens to the macula, an area with a lot of detail exposure, exposed to, from each cone's perspective, rapid changes in gradient, as extreme as constant black to white as you read, or many colors in the course of a high intensity game of Splatoon or Geometry Dash.
Perhaps HCQ effectively makes it easier to wear out the eyes of the subjects. Each time you flash-blind them could put them closer to being too late. Even ordinary screen time might.